The objective of this study was to evaluate the genetic control integrated to the chemical control of Asian soybean rust (ASR) and the effects of these measures on crop yield. The experiment was conducted in Erechim, Rio Grande do Sul State, Brazil, in 2016/17 and 2017/18 crop years, under a randomized block design, in a subdivided plot scheme (cultivars in the plots and fungicides in the subplots), with four replicates. The following cultivars were used: BMX Vanguarda (without ASR tolerance); TMG 7062; TMG 7262, and TMG 7161, tolerant to ASR (Inox™ Technology cultivars). The fungicides used were: T1) control (without application of fungicides); T2) azoxystrobin + benzovindiflupyr; T3) difenoconazole + cyproconazole; T4) trifloxystrobin + prothioconazole, and T5) epoxiconazole + fluxapyroxad + pyraclostrobin. Four fungicide applications were carried out at the V6, R1, R5.1 and R6 stages. During the experiment, for the calculation of the area under disease progress curve (AUDPC), disease severity was assessed at 7-day intervals in a random sample of 10 trifolia per plot. After harvest, yield components were determined: number of grains per plant, thousand grain weight (g), and yield (kg ha-1). In 2017/18 crop year, the fungicide difenoconazole + cyproconazole was not efficient for ASR control. The soybean cultivars TMG 7062, TMG 7161 and TMG 7261 delayed the disease progression; however, only TMG 7161 presented tolerance in the presence of the inoculum in 2016/17 and 2017/18 crop years. The association between chemical and genetic control is shown to be efficient for ASR control.

Asian soybean rust is an aggressive disease and chemical control must be handled assertively to minimize productivity damage. The objective was to evaluate systemic fungicides and multisite mancozeb, combined or not, and the effects on disease control and soybean yield, cv. 'BMX Lança'. The work was conducted in the field in the 2016/17 and 2017/18 crops, in a randomized complete block design, with four replications. The following treatments were evaluated: T+P) trifloxystrobin + prothioconazole; A+B) azoxystrobin + benzovindiflupyr; T+P+MB) trifloxystrobin + prothioconazole + mancozeb; A+B+MB) azoxystrobin + benzovindiflupyr + mancozeb; MB) mancozeb; and Control (without fungicide application). After the occurrence of the first symptoms of the disease, the severity (%) was evaluated in five trifolia per plot, every seven days, making it possible to calculate the area under the disease progress curve (AUDPC). The yield components and productivity (kg ha -1 ) were also evaluated. In both crops, the combination of systemic fungicides and mancozeb reduced the severity (%) and progress of Asian rust, reaching a control above 81%. Treatment with trifloxystrobin + prothioconazole + mancozeb (T+P+MB) obtained the highest percentages of control (94.5% -2016/17, and 93.7% -2017/18) of Asian rust, and provided, in the 2016/17 crop, productivity at 15 sc ha -1 , in relation to the fungicide applied alone (T+P). The combination of systemic fungicides and mancozeb, as proposed in this work, reduces the severity and progress of Asian rust and ensures the maintenance of the productive potential of the soybean.

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O trigo é um cereal importante devido as suas propriedades funcionais, tecnológicas e nutricionais. Contudo, a incidência de doenças como a mancha amarela e a ferrugem da folha, causam perdas significativas de produtividade. Objetivou-se avaliar a eficiência de diferentes fungicidas frente ao progresso e ao controle de mancha amarela e ferrugem da folha em trigo. O experimento foi instalado em delineamento em blocos ao acaso, com quatro repetições, na safra 2018, com a cv. BRS 374, sendo os tratamentos: T1) testemunha; T2) epoxiconazol + fluxapiroxade + piraclostrobina; T3) azoxistrobina + benzovindiflupir; T4) azoxistrobina + ciproconazol e propiconazol; T5) trifloxistrobina + tebuconazol; T6) piraclostrobina + metconazol; T7) piraclostrobina + epoxiconazol; e T8) protioconazol + trifloxistrobina. Avaliou-se a área abaixo da curva de progresso da doença (AACPD) e o controle (%) para mancha amarela e ferrugem da folha; peso hectolítrico (Ph), peso de mil grãos (PMG, g) e produtividade (kg ha-1). O fungicida epoxiconazol + fluxapiroxade + piraclostrobina obteve melhor controle alcançando 85,5% (mancha amarela) e 88,2% (ferrugem da folha). Os tratamentos com epoxiconazol + fluxapiroxade + piraclostrobina, azoxistrobina + benzovindiflupir, piraclostrobina + metconazol e protioconazol + trifloxistrobina apresentaram os melhores resultados, incrementando a produtividade em 37,4%, 38,0%, 39,4% e 43,8%, respectivamente.